The present invention relates to an improved selvage forming device, and more particularly relates to improvement in construction of a device for forming selvages of woven cloths by twisting leno warps with ground warps.
Twisted weave is classified into gauze and leno weaves and made up of twisting warps, ground warps and wefts. In the case of leno weave, twisted warps, i.e. leno warps, are always located on wefts. The present invention contemplates improvement in formation of selvages for woven cloths utilizing the art of leno weave.
In formation of a course of leno weave, one or more leno warps have to be alternately distributed onto different lateral sides of a ground warp once per prescribed number of picks so that the leno warps twist around the ground warp. Although various devices have been conventionally proposed to carry out this distribution of leno warps, they are almost all accompanied by at least one of the following drawbacks.
(i) In order to form sufficiently stout selvages, it is necessary to enlarge and complicate the construction of the device.
(ii) A lot of movable elements are required to carry out very intricate movements, thereby causing increased mulfunctions and shortening the life of the device.
(iii) Since the leno warps contact the thread guide elements at limited sections of the latter, sharp depressions are formed in the contact sections of the thread guide elements, which tend to cause frequent yarn breakages and generation of fluffs on the leno warps. In order to avoid such troubles, frequent replacement of such thread guide elements is required which apparently leads to disadvantage in economy and increased labour.
(iv) Due to intricate movements of the related mechanical elements, the device is unable to well follow high speed running of weaving looms. It is also difficult to have increased courses of leno weaves in a single selvage construction.
(v) Due to intricacy in construction, a lot of mechanical elements are neither visible nor accessible from outside of the device. This often leads to delayed detection of abnormal operations and difficulty in maintenance.
(vi) Leno warps are subjected to large bending at distribution, thereby causing undesirable damages on the leno warps and degradation of woven cloths produced.